The rising risk of curtailment is putting pressure on owners of renewable energy plants in Japan. In the absence of support measures, the curtailment rate in Japan is likely to worsen as installed PV capacity continues to grow.
The frequency of curtailment of renewable power generation in Japan will be higher in the spring as high power supply meets low demand. During the holiday period from late April to early May, there were power outages in four regions of Japan. 22% of renewable electricity generation was discarded for half an hour on April 30, the highest level ever recorded in the region.
As renewable energy penetration continues to rise, curtailment rates are likely to worsen. It is expected that by 2025, Japan's cumulative installed photovoltaic capacity will reach 97GW, an increase of 24% from the current level.
To encourage daytime electricity use with higher photovoltaics, Japan will require utilities to set time-of-use tariffs from April 2023. To alleviate the curtailment problem, Japan could also consider installing more energy storage systems and expanding cross-regional transmission lines to deliver more power to demand centers.
